Insulators are used on utility poles and towers to prevent electricity flowing through wires, frequently at a very high voltage, from being discharged to the ground or other wires.
A typical pin type insulator is fixed to a pole or tower crosspiece and has an upper saddle portion on which the wire rests. Till now, most commonly a wire has been attached to its insulator by manually winding and twisting a small diameter wire around the electrical wire and the saddle portion.
Such method and means of attachment is unsatisfactory for four reasons:
(1) it is difficult for a workman who must also climb or be hoisted to live wires in a crane bucket, to effect the tricky winding of the small diameter wire, using a tool with a six-foot insulated pole;
(2) it is time-consuming;
(3) such means of attachment does not prevent the electrical wire from slipping away over the insulator in the event that the wire is severed, for example, by a falling tree, in a windy storm, such being possible because the utility poles or towers are usually quite far apart from each other, resulting in relatively heavy lengths or suspended wire between insulators, and thus, if a wire is broken, its weight will tend to pull downwardly and across an insulator against the wound small diameter wire; and
(4) tie-wires are known to cause radio interference of the AM band.